| Summary: | 碩士 === 國立清華大學 === 應用科學系所 === 106 === During the past few decades, people use the fossil fuels to produce energy. The consequence of the use of fuels is the excessive emission carbon dioxide to the Earth's atmosphere, that creating the greenhouse effect. The lithium silicates use as high-temperature sorbents for carbon dioxide capture in an attempt to alleviate the consequences of global warming.
For the preparation of lithium silicates nanomaterials from recycled silicon powder or broken silicon wafers and LiOH‧H2O by hydrothermal method only and precipitation method with calcine. Reactions were performed with different Li:Si molar ratios of 2, 4 and 8. The synthesized products were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). The obtained products were Li2SiO3, Li4SiO4. Li2SiO3 prepared by hydrothermal method and precipitation method with calcine. We could calculate dimension from XRD FWHM, and Dhkl= 15~55nm. Pure Li4SiO4 only prepared by precipitation method and calcined at 800℃ for 3 hours or 900℃ for 2 hours. Li4SiO4 nano thin film would be observed by precipitation method and calcined at 900℃ for 2 hours.
Finally, the Li2SiO3 have been doped with Eu3+. PL emission spectrum of Eu3+ doped Li2SiO3 taken with excitation at the 230 nm, a number of sharp lines were observed at 590(green light)、612nm(orange light) and 705nm(red light).
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